(Newser)
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Dilma Rousseff was sworn in as Brazil's first female president today, capping a rapid political trajectory for the career technocrat and former Marxist rebel who was imprisoned and tortured during the nation's long military dictatorship. Rousseff, 63, takes the helm of Latin America's largest nation, which has risen both financially and politically on the world stage under outgoing leader Luiz Inacio Lula da Silva.

Silva leaves office as the nation's most popular president with an approval rating that hit 87% in his last week in office. Rousseff was his hand-chosen successor, and takes on the formidable task of maintaining Brazil's momentum: Under Silva, Brazil cut poverty while its economy boomed, and it is expected to be the world's fifth-largest economy by 2016. Huge challenges also await Rousseff, like managing the sweeping improvements Brazil needs in its infrastructure, security, and education. Click for more on Rousseff, called the world's most powerful woman.